From 00c90a36f723fb24cce340db3aaadeac2d26c23b Mon Sep 17 00:00:00 2001
From: fvogel <fvogelnew1@free.fr>
Date: Sun, 28 Dec 2014 18:00:53 +0000
Subject: Further fixed text count -ypixels with indices in elided lines,
 [30d6b995dc] was not always correct

---
 generic/tkTextDisp.c | 44 ++++++++++++++++++++++++++++++--------------
 tests/textDisp.test  | 14 +++++++++++++-
 2 files changed, 43 insertions(+), 15 deletions(-)

diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index ae9c341..be77550 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -3603,29 +3603,44 @@ TkTextIndexYPixels(
 {
     int pixelHeight;
     TkTextIndex index;
+    int alreadyStartOfLine = 1;
+
+    /*
+     * Find the index denoting the closest position being at the same time
+     * the start of a logical line above indexPtr and the start of a display
+     * line.
+     */
 
     index = *indexPtr;
-    TkTextFindDisplayLineEnd(textPtr, &index, 0, NULL);
+    while (1) {
+        TkTextFindDisplayLineEnd(textPtr, &index, 0, NULL);
+        if (index.byteIndex == 0) {
+            break;
+        }
+        TkTextIndexBackBytes(textPtr, &index, 1, &index);
+        alreadyStartOfLine = 0;
+    }
 
     pixelHeight = TkBTreePixelsTo(textPtr, index.linePtr);
 
     /*
-     * Iterate through all display-lines corresponding to the single logical
-     * line belonging to index, adding up the pixel height of each such
-     * display line as we go along, until we go past 'indexPtr'.
+     * Shortcut to avoid layout of a superfluous display line. We know there
+     * is nothing more to add up to the height since the index we were given
+     * was already the start of a logical line.
      */
 
-    if (index.byteIndex == 0) {
-	return pixelHeight;
+    if (alreadyStartOfLine) {
+        return pixelHeight;
     }
 
-    index.tree = textPtr->sharedTextPtr->tree;
-    index.linePtr = indexPtr->linePtr;
-    index.byteIndex = 0;
-    index.textPtr = NULL;
+    /*
+     * Iterate through display lines, starting at the logical line belonging
+     * to index, adding up the pixel height of each such display line as we
+     * go along, until we go past 'indexPtr'.
+     */
 
     while (1) {
-	int bytes, height;
+	int bytes, height, compare;
 
 	/*
 	 * Currently this call doesn't have many side-effects. However, if in
@@ -3637,9 +3652,10 @@ TkTextIndexYPixels(
 
 	height = CalculateDisplayLineHeight(textPtr, &index, &bytes, NULL);
 
-	index.byteIndex += bytes;
+        TkTextIndexForwBytes(textPtr, &index, bytes, &index);
 
-	if (index.byteIndex > indexPtr->byteIndex) {
+        compare = TkTextIndexCmp(&index,indexPtr);
+        if (compare > 0) {
 	    return pixelHeight;
 	}
 
@@ -3647,7 +3663,7 @@ TkTextIndexYPixels(
 	    pixelHeight += height;
 	}
 
-	if (index.byteIndex == indexPtr->byteIndex) {
+        if (compare == 0) {
 	    return pixelHeight;
 	}
     }
diff --git a/tests/textDisp.test b/tests/textDisp.test
index 6c21700..954c1f6 100644
--- a/tests/textDisp.test
+++ b/tests/textDisp.test
@@ -2692,7 +2692,6 @@ test textDisp-19.17 {count -ypixels with indices in elided lines} {
       [.t count -ypixels 25.4 27.50] \
       [.t count -ypixels 35.0 38.0]
     .t yview 35.0
-    update
     lappend res [.t count -ypixels 5.0 25.0]
 } [list [expr {4 * $fixedHeight}] [expr {3 * $fixedHeight}] 0 0 0 0 0 0 [expr {5 * $fixedHeight}] [expr {- 5 * $fixedHeight}] [expr {2 * $fixedHeight}] [expr {3 * $fixedHeight}] [expr {5 * $fixedHeight}]]
 test textDisp-19.18 {count -ypixels with indices in elided lines} {
@@ -2712,6 +2711,19 @@ test textDisp-19.18 {count -ypixels with indices in elided lines} {
     update
     lappend res [.t count -ypixels 5.0 25.0]
 } [list [expr {5 * $fixedHeight}] [expr {5 * $fixedHeight}]]
+test textDisp-19.19 {count -ypixels with indices in elided lines} {
+    .t configure -wrap char
+    .t delete 1.0 end
+    for {set i 1} {$i < 25} {incr i} {
+        .t insert end [string repeat "Line $i -" 6]
+        .t insert end "\n"
+    }
+    .t tag add hidden 5.27 11.0
+    .t tag configure hidden -elide true
+    .t yview 5.0
+    update
+    set res [list [.t count -ypixels 5.0 11.0] [.t count -ypixels 5.0 11.20]]
+} [list [expr {1 * $fixedHeight}] [expr {2 * $fixedHeight}]]
 .t delete 1.0 end
 .t insert end "Line 1"
 for {set i 2} {$i <= 200} {incr i} {
-- 
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